Any child learning a tiny bit of physics will know, that magnetic material gets magnetised.
Otherwise the plunger of our dear solenoids could not be held in place!

This picture shows a plunger I just pulled out of a white solenoid. Then I touched it with a screwdriver and surprise surprise,
the plunger does not fall of. And no, it's no magic, it's no glue.....
but I give you a clue:

It's magnetism!

I have no time to respond to all your other statements.
But just to make this sure:

I had sent copies of the original datasheet to moderators previously because when I make statements about its origin etc. those are statements about facts and not guesswork.

There is a reason why it is not going to be published but just to make this a final statement:

The company who manufactures the solenoid is a Japanese company and moved its plants to China.
The first time the green China-made solenoid was built into a Pentax was into the flashcircuit of the K100D.
The first time it was used in the aperture-circuit was with the introduction of the K-30.

The material of the white Japan made solenoid is PTFE and any person who has worked with this kind of PTFE can easely distinguish the difference between PTFE and the much cheaper PET (green solenoid body). I have worked with PTFE in the past for bearings. I have worked and developed precision electronics for over 40 years and I know what I speak about. I have soldered electronic parts with the help of the microscope, soldering a solenoid is kind of kindergarden compared to this.

All the rest is unimportant, I know very well what I speak and write about.

Time to demagnetize your screwdriver, I'd say. This is no valid magnetization test, using two parts either of which may be magnetized, that's just ridiculous and if your expertise is on that level you should keep it to yourself.

Your other statements still aren't helpful without links or sources.

I've said what I've got to say and this is it for me, I won't fall for your bait and go your way endlessly repeating myself. So EOD here.

There are no camera solenoids listed there, though. Datasheet doesn't mention type of plastic material. 20.000 actuations also is not a lot. A pause of 5secs between actuations is also not matching the Pentax part.

So, why the secretiveness? It's all public. But there's no mention of camera solenoids, the ones in the list are destined to CD drive doors.

Now what we still don't know is if they made the part for Pentax, especially because this is not the only manufacturer of this kind of solenoid, what one could assume is that if they did, it was a tailor made part, made according to Pentax' wishes.
Or it's a red herring and someone else makes those parts.

So, why the secretiveness? It's all public. But there's no mention of camera solenoids, the ones in the list are destined to CD drive doors.

Now what we still don't know is if they made the part for Pentax, especially because this is not the only manufacturer of this kind of solenoid, what one could assume is that if they did, it was a tailor made part, made according to Pentax' wishes.

Pentax doesn't commission parts like this. They use a generic part out of a catalog. In fact. that is part of the problem - the producer changed how they construct the part, apparently without telling Pentax or even changing the number; Pentax kept their same numbers, so they had no realization that anything had changed, nor do they have any way to trace back in their database. And, yes, users who do solenoid transplants sometimes go to old CD devices to get an appropriate solenoid.

You can look at the history page (that our estimated colleague has censored above) in its unblemished glory.

Shinmei Electric

I see they moved the manufacturing to Taiwan in 1973. Which means the solenoids were made in Taiwan (China) as early as 1973, not Japan.

Originally posted by reh321

Pentax doesn't commission parts like this. They use a generic part out of a catalog. In fact. that is part of the problem - the producer changed how they construct the part, apparently without telling Pentax or even changing the number; Pentax kept their same numbers, so they had no realization that anything had changed, nor do they have any way to trace back in their database. And, yes, users who do solenoid transplants sometimes go to old CD devices to get an appropriate solenoid.

From the product sheet:
1. The appearance and specifications of the products may be modified without prior notice to improve its performance.
2. This catalogue shows only outline specifications. When using the product, please obtain formal specifications.
3. Please see appendix [How to select solenoid].
4. Please confirm the performance on actual operation by simulation with actual environments for high reliability.
5. Please avoid the storage in dusty environment. If you store the products for a long time, do not keep open the
package.
6. Please take care for the usage in high humid atmosphere and design-in to meet the operating condition of the device,
for the coil resistance increases 0.4%/degree Celsius depending on the operating ambient temperature.
7. Please feel free to contact us for the models with other coil resistances.

From the product sheet:
1. The appearance and specifications of the products may be modified without prior notice to improve its performance.

This is one of the problems in using a 'stock' part ..... their definition of "improve" may be different than yours ..... and I'm guessing Pentax got no notice at all of any changes to "appearances and specifications".

Time to demagnetize your screwdriver, I'd say. This is no valid magnetization test, using two parts either of which may be magnetized, that's just ridiculous and if your expertise is on that level you should keep it to yourself.

Nonsense: If the plunger is made of material which can be magnetized ..... it will be attracted by a (yes, quite right..) magnetized tip of a screwdriver as well! That was the point!

But to bring that point closer to those really interested:

If you place the plunger of the green solenoid on a surface as well as the plunger of the white solenoid and you carefully move the tip of this very magnetized screwdriver (yes, you got that right, a magnetized tip of this very screwdriver!) then you can notice that you can come about 50% closer to the plunger of the white solenoid until it suddenly moves/clings to the screwdriver tip! Why? Very simply because the plunger of the green solenoid is magnetized more than the one of the white solenoid! So go figure!

Originally posted by sys3175

Your other statements still aren't helpful without links or sources.

Ah... and you have brought how many links or sources to this theme? Zero!
My statements are not helpful for you because you are not interested. Like this magnetized plunger is stuck to the tip of the very magnetized tip of the screwdriver you are stuck to opposition for the sake of opposition. And no, I am not hijacking threads. I put straight such faults like for example faults in this post:

Because this person recommends solenoids from CD-Rom drives (which you did as well) and thus actually misleads others who don't know!

He mentions the different size of the magnet (giving them another holding-force) and he mentions a strange impedance of 15 ohms for the green K30 solenoid and 26 ohms for the CD Rom solenoid. Well, maybe this is due to the cheap (green) chinese multimeter he uses but I suspect he mixed up both values because the green K30 solenoid ALWAYS has 30 ohms!

But most Rom-solenoids 15 ohms. But in most cases they have this different holding force. And this is the very point. The wrong impedance and the different holding force can lead as much to further damage as does sanding the plunger of the green solenoid with I will proof with photos soon, the work is already done:

I have the whole aperture mechanism on my workbench and built the normal green solenoid, a green one with sanded plunger and the white Japan solenoid into it. The results are absolut clear as best clear spring water:

The plunger of the green solenoid not sanded tilts already quite clearly to the side!

More so the plunger of the sanded solenoid tilts

But the plunger of the white solenoid remains nice and straight!

Originally posted by sys3175

I've said what I've got to say and this is it for me....

we shall see

Originally posted by sys3175

I won't fall for your bait and go your way endlessly repeating myself. So EOD here.

There was never any discussion! There was just discursive arguing based on zero real investigation from your side.
Kind of "anti" for the sake of anti. But you falling for my bait.... c'mon, give us a break.... this is sandpit behaviour. Well, at least it matches the sanding-method.

So, to put this one straight as well, if you do some research, go the whole hog instead to remaining hooked in your anti-no-saying position:

Originally posted by sys3175

There are no camera solenoids listed there

Good for the person who has eyes to read and investigates properly:
Of course Shinmei manufactures solenoids for cameras and the mentioned solenoid is the very one used in the Pentax K30 etc.

I have purchased exactly these solenoids (from Shinmei!) and they are exactly the ones built into the Pentax cameras since the K100D (flash)
and K30 (aperture circuit)! Period!

But of course they are useless for repair, as they will fail again and have proofed to fail.

I purchased them for research.

I never would dare to use it in a Pentax DSLR. Sanded or "as it is".

As said this is going to lead to further damage and I have the proof and will later on publish it here in this forum!

The only important thing is how to do this the best way and this is what I always stood for in this forum.

Originally posted by reh321

This is one of the problems in using a 'stock' part ..... their definition of "improve" may be different than yours ..... and I'm guessing Pentax got no notice at all of any changes to "appearances and specifications".

Quite right! And this was the reason I did not want the papers to be made public, because it is food for those Pentax bashers and food for those greedy for sensationalism. Sys3175 had only his hunger for sensationalism in mind. There was zero though about why not to publish it. Just the urge to "be important".....look... I found it.. and I bring it forward to you all..
It was my stupid fault, I gave him the bait without realising, well... he snapped pretty quickly.

Originally posted by Not a Number

I see they moved the manufacturing to Taiwan in 1973.
Which means the solenoids were made in Taiwan (China) as early as 1973, not Japan.

..it seems that most collateral damage occurs under the top plate of the camera where there are some sensitive ribbon connectors that are easy to screw up; I would recommend not removing the top, just loosening the screws a bit so that the other panels can be wiggled out.

Another common problem is that the AF switch gets misaligned during reassembly

because as you say, then you have to "wiggle out" the panels instead of gettin them out with ease because.... as I have recommended many times.. youdon't take the top part off completly but you lift it that bit prior taking all screws out completly (and never just loosening them) so that particular the front part can just be lifted instead of senseless wiggling and fiddling! This will give you also the needed access for removing and soldering the solenoid! If one would follow your advice there is not enough access to the solenoid, it sits too close to the top part and one could easely to more damage.
But also it will make the alignement of the AF-C-M switch much more difficult because you have to wiggle and fiddle and push to get the front part back in and

the alignement of this switch is then trial and error, which is to be avoided, because you can bend a part and then it is very difficult to get this back into proper alignement!

Simply by watching the screwdrive rod of the screwdrive motor being in the correct position, i.e. it peeps out of that tiny hole of the k-mount right next to the AF/C/M switch.

Or the otherway round: External switch on M (the rod retreats) and the inner part upwards. Works as well of course. The inner part moves pretty easy so this is what has to be checked prior assembly. After putting the front part back on one checks that with moving the AF/C/M switch this rod moves in and out.

But now we come to your last wrong advice:

Originally posted by sys3175

And be careful not to touch the contacts of the flash condensor (battery-like object on the side where there's no grip), it may be charged with high voltage

.
Nobody will touch the contacts of the flash condensor because both contacts are well protected!
One would have to poke inside this gap for this.

The shock could be that strong that one might drop the camera or,
if it is during soldering because one does hold the camera on that side, it is pretty possible that the hot tip of the soldeing iron will damage other parts because one moves in uncontrolled.

One has to give very clear instructions about when this high-voltage charged (and enough amperes to give a shock) electrolytic flash condensor is not charged, how to avoid charging and, if it is charged, how to discharge it!

i could ask few tech people who might have some, because my k-50 is already beyond 55'000 shots and paying more than 40 bucks at ebay for it isn't too tempting. also i wouldn't risk to change the failed one for another green item, it can die just after few hundreds/thousands of shots again.

i could ask few tech people who might have some, because my k-50 is already beyond 55'000 shots and paying more than 40 bucks at ebay for it isn't too tempting. also i wouldn't risk to change the failed one for another green item, it can die just after few hundreds/thousands of shots again.

I would say no. The resistance is too low. The correct one is 30 Ohms.

i could ask few tech people who might have some, because my k-50 is already beyond 55'000 shots and paying more than 40 bucks at ebay for it isn't too tempting. also i wouldn't risk to change the failed one for another green item, it can die just after few hundreds/thousands of shots again.